Ignition-control mechanism



Nov. 13,

B. DICK IGNITION CONTROL MEcHANIsM Filed Oct. 22, 1923 2 Sheets-Sheet l llNyENToR Kim/n4 #Qtr/ BY TTORNEY Nov. 1-3, 192s. 1,691,157

B. DICK IGNITION CONTROL MECHANISM Filed oct. 22. 1925. 2 sheets-sheet., 2

INVENTOR BY TORNEY Patented Nov. 13, 1928.

UNITED STATES PATENT OFFICE.

BURNS DICK, OF ST. LOUIS, MISSOURI, ASSIGNOR T0 WAGNER ELECTRIC CORPORATION,

OF ST. LOUIS, MISSOURI, A CORPORATION OF DELAWARE.

IGNITION-CONTROL MECHANISM.

Application led October 22, 1923. Serial 110.669,90?. 1

My invention relates to spark controlling mechanism for internal combustion engines by means of which the time of spark occurrence with respect to a given engine piston 5 position may be automatically changed and also a predetermined relation of the extent of change to the speed of the engine may be secured; that is to say, by means of my invention itis possible to cause the spark to i0 be advanced either proportionatelyv to the speed of the engine, or in Vother relations to the speed. In automatic advance mechanism now in general use the relation of spark ad vaiice to engine speed is determined by the re lation of centrifugal force to speed and the angle of the line of connection between the weight and the timing cani to a line from the center of the cam shaft to the connection point on the weight. Broadlyspeaking, my

' 20 invention comprises the provision of means for introducing a third factor into the determination of the resultant curve of advance,

this means serving to increase in a predetermined relaton to vengine speed the spring resistance to the outward motion `of the weights. In this manner it is possible to secure a wider range of curves of advance in relation to speed than can be secured by any permissible variation of the angle o f con` '8o nectlon of the weights to the cam previously referred to, and it is also possible to produce 'lthe curve most suitable for each particular type of engine, it being well understood that a spark advance relation most desirable for t5 a high compression engine differs from that for engines designed for lower compression ranges. I l

Inthe accompanying drawings F igure'l is a. vertical cross-sectional view of a timer dis- 40 tributor mechanismv embodying my invention; Figure 2 is a bottom plan view; Figure 3 is a plan view of the governor mechanism with a portion of the Weight carrying meinber broken away and being substantially a sectional view along the line 2%3 of Figure l 1; Figure 4 isatop plan `View of the mechanisni shown in Figure 1 with the casing and distributor disk removed; and Figure 5 is a crosssectional view along the line 5-5 of Figure 1, the condenser 2() being omitted.

The main supporting casting 1 of the timer distributor mechanism is designed for insertion into a suitable mounting on the .engine or' generator driven thereby and carries the shaft 2, which is connected by suitable means not shown) to be driven by the engine. This shaft drives the ignition timing and distributing mechanism part of which is Acontained in the compartment formed by the removable cap 3 carrying the high tension distributor terminals and the cylindrical casing 4 mounted on the main supporting casting l. The distributor mechanism comprising the distributor disk 5 mounted on the end of the shaft 2 and cooperating with the high tension terminals referred to forms no part of my invention and since this mechanism may be of any well known type it will not be further described. y rl`he circuit breaker arm 6 is mounted on the side of the support 1 and enclosed by removable cover 19. It is actuated by a. loosev is capable of a limited angular-motion with respect to said shaft, by reason of the fact that the upper end of the sleeve on which the cam faces are formed, is provided wit-h a slot in which is located a key 9'which passes through the shaft 2. The relative sizes of the key and slot determine the maximum eX- tent of possible rotation of the cam sleeve with respect to the shaft. It is by such relative motion that the timeof occurrence of i shown is approximately an S-shaped plate,

is carried by a hub 11, keyed to the shaft 2.

This plate carries the pivots 12, on each of which is mounted a weight 13. These weights are each connected by a link 14 to flange 15 on the cam sleeve 8. The Hat springs 16 have one end rigidly supported on the weight, and the inner ends of these springs contact with the curved surfaces forming the inner faces of the ends of the S-shaped governor member 10. Curved back plates 17 engaging with the springs adjacent to their supports on the weight, serve to control the bending of the springs. at these points and reduce the liability of breakage, which might result from los " too great a deflection at a single point. The

other ends of the springs pass through guide retainers 18, carried by the plate 10.

Referring Ynow to the operation of the governor mechanism, the springs 16 vare adapted to hold the weights in their retracted position shown in Figure 3, whenthe a paratus is stationary. When the timer s aft.

is rotating the infiuence of centrifugal force Ycauses the freeends of the weights to move,

outward against the resistance of the springs 16 andby reason of the link connection between these weights and the cam sleeve 8, this sleeve is rotated with respect to shaft 2 and the time of circuit breaker interruption is thereby7 advanced with respect to specific engine piston position. Since the extensions on the governor plate 10 form curved stops for the ends of the springs, the area of contact between the springs and these stops increases as the weights move outward and the effective length of the springs is thereby shortened and theiigresistance to the motions of the weights is increased. The shape of these stop curves can be so chosen as to govern the rate of increase of spring tension in a desired relation to the speed of the engine and it is therefore possible to select a curve which will cause the resultant curve of spark advance to be most suitable for the particular engine in connection with which the, mechanism is employed.

1 am aware that modifications in the particular mechanism shown may be made and I therefore do not desire that the scope of my invention be limited otherwise than by the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a centrifugal governing device for the ignition means of an internal combustion engine, the combination of a pivotally mounted weight, a resilient member having one end fixed to the free end of the weight to 'be nonrota'table with respect thereto, and means forming a curved stop engaged by the spring, said stop being so positioned relative to the spring that the point of contact between the spring and stop moves toward the fixed end of the spring as the weight travels outward under the influence of centrifugal force.

2. In ignition mechanism for internal combustion engines, the combination of a shaft driven by the engine, an ignition timing cam driven by the shaft through connections permitting angular movement of the cam with respect to the shaft, a governor member mounted on the shaft and rotating therewith, a weight pivoted to the governor member, connections between the cam and weight for shifting the angular position of the cam, a spring having one end attached to the weight, and means on the governor member forming a curved stop for` the spring, the relation of the curve of the stop to the spring being such that the effective length of the spring will bedecreased by the outward motion of the weight.

3. In ignition mechanism for internal combustion engines, the combination of a shaft driven by the engine, an ignition timing cam driven by the shaft through connections permitting angular movement of thev cam with respect to the shaft, a governor member mounted on the shaft and rotating therewith, a weight pivoted to the governor member, connections between the cam and weight for shifting the angular position of the cam, a flat spring having one end rigidly attached to the weight, an extension of the governor member having a curved edge in position to contact with the other end of the spring, the curve of said edge being so located with respect to the spring that the distance from the supported end of the spring to the nearest point of contact of the spring with governor member extension is less when the lweight is at a point intermediate its limits of travel than in its retracted position.

4. In ignition mechanism for internal comi bastion engines, the combination of a shaft driven by the engine, an ignition timing cam driven by the shaft through connections per- .mitting angular movement of the cam with respect to the shaft, a substantially S-shaped governor member mounted on the shaft and rotating therewith, two weights each pivoted to the governor member on opposite sides of the shaft, connections between the cam and each weight for shifting the angular position of thecam, two flat springs each having one end rigidly attached to a weight, said governor member having curved edges in position to contact with one end of each spring, the curve of said edges being so located withlrespect to the springs that the distance from the supported end of each spring to the nearest point of its contact with the governor member is lesswhen the weight is at a point intermediate its limits of travel than in its retracted position.

In testimony whereof, I have hereunto set my hand.

BURNS DICK. 

